HTML5 <audio autoplay> Not Working

Is there a way to configure Screenly OSE browser to autoplay mp3 audio files? For example:

<audio src="music.mp3" autoplay></audio>

Does not autoplay the mp3 file “music”. This will work outside of Screenly OSE with a Firefox browser that is configured to allow autoplay.

I am not 100% on this, but I dont think the Qt web browser compiled for Screenly OSE which is mostly non-audio stuff, was compiled with support for audio.
The reason I say this without asking the person that compiled it is because according to Qt’s document, you need to pass the webengine proprietary codec parameter when compiling, along with whatever other features you want it to have, and if you search for this on Github, you can see whose code has it:

But, if you search for this same codec line in the Screenly org, it doesnt exist: